Bioaccumulation and human health risk assessment of polychlorinated biphenyls (PCBs) in farmed oysters along Guangdong coast

We analyzed 30 congeners of polychlorinated biphenyls (PCBs) in the farmed oysters (Crassostrea rivularis, C. hongkongensis, C. gigas) from the main aquaculture areas along Guangdong coast (Shantou, Shanwei, Shenzhen, Zhuhai, Jiangmen, Yangjiang and Zhanjiang) by using gas chromatography mass spectrometry (GC/MS). The detection rates of PCBs in oysters and their potential risks to human health were also evaluated. Results show that PCBs had a detection rate of 97.6% in the farmed oysters along Guangdong coast. Concentration of PCBs in oysters ranged from nd to 8.62 ng·g⁻¹ (wet mass), with an average value of (0.57±1.23) ng·g⁻¹. The highest PCBs concentration was found in Shenzhen, followed by Zhuhai, Shantou, Yangjiang, Jiangmen, Zhanjiang and Shanwei. The congeners of PCBs and their compositions were similar in different locations, showing that Hexa-PCBs and Penta-PCBs are the most abundant components in oysters. Compared with the shellfish in other coastal waters at home and abroad, the concentration of PCBs in this study is at a lower level. Bioaccumulation of PCBs in farmed oysters is lower than the limited residue levels of PCBs in National Food Safety Standard Limits of Pollutants in food in China and the hygienic standard for shellfish in European Union. The carcinogenic risk and hazard quotient of PCBs in oysters are less than the threshold value of the US Environmental Protection Agency, indicating that the carcinogenic risk of indicator PCBs in Guangdong oysters is at an acceptable level for consumers.